Curtain-stretcher clamp



Patented June 21, 1927.

UNITED STATES PATENT OFFICE.

CHARLES G. CARLSON, or CHICAGO, ILLINOIS."

. CURTAIN-STRETCHER CLAMP.

Application 'led February 6, 1926. Serial No. 86,404.

clamps, and also to avoid the imposition of heavy pressures which might tend to crush or mar the wood of the curtain frame rails.

Another object of the invention is to so arrange the parts that they may be readily stamped out of strips or plates of metal and readily assembled at a minimum cost.

A further object isto provide means for certainly and effectively guiding the pressure element in the clamp, so that it will slide freely under the thrust of the adjusting screw, and to otherwise improve the construction and arrangement of the device as a whole.

In the drawing:

Figure 1 is a corner of a curtain frame showing the clampiof the present invention in clamping relation;

Fig. 2 is an enlarged elevation of the part shown in Fig. 1, taken at right angles to the disclosure of said figure;

Fig. 3 is a cross sectional view taken on line 3-8 of Fig. 2, looking in the direction of the arrows; and

Fig. 4 is a side elevation of a modified form of clamp.

The clamps of Figs. 1, 2 and 3 are of generally U-shaped formation comprising side plates 10 and 11. the latter of which is of greater length than the former, which side plates are connected by a cross head 12 best shown in Fig. 3. The side plates 10 and 11 are secured to the front and rear faces respectively of a frame rail 12 by provision of rivets l'and 14- respectively, the latter of. which passes only through the extended rear plate 11. This furnishes a loop shaped fitting in the .form of an extension rigidly secured to the frame rail 12' in position to receive the end of the adjoined lframe rail 15.

The clamp is provided at its head end with an adjustable abutment 16 comprisingr an inner contact plate 17 adapted to abut squarely against the outer edge of the frame rail 15, which contact plate has backwardly turned therefrom a pair of spaced parallel guide walls 18 which'are somewhat narrower in width than the contact plate save at they `Y extreme outer ends where said walls are laterally extended to afford stop shoulders `19. The lguide walls 18 lie within cuts or recesses 2O in the proximate edges of the cross head 12 which thus furnish guideways for the in and out adjusting movements imparted to the abutment.

The abutment is adapted to be adjusted by means of a screw 21 having a handle or thumb piece 22 at its outer end, which screw f is threaded through the center of the cross head 12 and bears directly against the center of the back face of the contact plate 17, so that by turningthe screw, the abutmentl will, be forced inwardly to the extent permitted by the stop shoulder 19. The arrangement is one which affords movement within the limits measured by the length of the narrow portions of the guide walls 18, and, at the same time, prevents loss or displacement of the abutment member when out of contact with the frame rail.

In order to provide ample clearance for the movable pins 22 which travel in the undercut channel 23, the overlying bridge portion 24 of the front plate 10 is slightly elevated which affords the necessary clearance for the pins without unduly Vdeepening the undercut channel in which the pins are guided. In order to afford sufficient stockfor the threading of the adjusting screw 21 through the head 12, the metal of the head, at the point adjacent to the threaded bore, is flanged inwardly to afford a boss 25 which serves to extend the threading sufficiently to ensure a full threaded engagement with the screw.

In the modification illustrated in Fig. 4., the clamp comprises front and rear plates 26 and 27 with a cross head 28, but in this insta-nce, the rear plate 27 only is rigidly secured to the'frame rail 12 by the provision ofrivets 29. This leaves the front plate 26 tree to be clampedy against the front face of the frame rail 15 by the tightening up of a thumb nut 30 on the front end of a draw bolt Bl, which draw bolt extends through.

ftive in affording a tight clamping action between the rails by reason of the fact that the abutment member affords a broad flat zur,

Y surface of contanti `with enexhendedifnma along the edge of the rail 15,so that under moderate pressure, the engagement willlbe suiliciently rm to tightly`` holdtiie parts together without any tendeneyl to crush- 4the Wood or to Center the pressure at a single "Vmiais to `pnedvent bindingl or cramping; Furftrlilemnere, tlieffconmet plate 17tl1eedges. of

`wl'lirieirbeen squenelbnagainst the innen tenes ofthe liront zmdl been plantes: 10; and 1-1, isr strlengtliened` andi reinforced thavtthere isfno bendingfon buckling against the nearvinemlly` turneda guide Walls* i8. which thus not only subserve a1 guiding vfunction. but` also?. impart` strength and? nigidity 'tofV the tnng; 1 u

"netedt their' outer` endsby e cross head 25 provided with gnideslotsin its exposed j edges, en abutment member: comprising@ f jecting" beyond theslots in the cross head to limit; the sliding movement of the `abutment ineinber,` and an adjusting screw entered threugln the cross and Abearing against thema-1' vsurface-of the arbutiinmt member, substantially es; describedi i 241211; m itl-empfoncurtain frnniesrend. the

lilie,` the; combination of, spaced plates, conj nentedi atjthein upper ends loylv the Gross head provided with guide slots in; its exposed edges, an abutment member comprisinf: ai contant lfiance plate subtenfli'ng the Spae'beiiweeni the plates, andi nearwardly ,extending Walle embraeing and gui ded? Withl imtheslotted: edges in the @ross heed,L and 1". In. a clamp for cuntniinlframesy oi* the Y like,` the comin-nationoi'y spaced plates conemesA heedandbea-ringg against the reep surfiwe o the abutment member substantially asdescribedi. C d CHARLES (LCAJRLSON. 

